Idris is a general purpose language with full dependent types.
It is compiled, with eager evaluation.
Dependent types allow types to be predicated on values,
meaning that some aspects of a program's behaviour can be
specified precisely in the type. The language is closely
related to Epigram and Agda. There is a tutorial at
http://www.idris-lang.org/documentation.
Features include:

Readme for idris-0.9.20.1

Idris

Standard Installation Instructions

This repository represents the latest development version of the language,
and may contain bugs that are being actively worked on.
For those who wish to use a more stable version of Idris please consider
installing the latest version that has been released on Hackage.
Installation instructions for various platforms can be found on the Idris Wiki.

Installing Development Versions

If you like to work against the latest development version, please consider
using Cabal Sandboxes to minimise disruption to your local Haskell setup.
Instructions for installing Idris HEAD within a cabal sandbox are
available on the Idris Wiki.

To configure, edit config.mk. The default values should work for most people.

Idris is built using a Makefile common targets include:

make This will install everything using cabal and
typecheck the libraries.

make test This target execute the test suite.

make relib This target will typecheck and recompile the standard library.

Idris has an optional buildtime dependency on the C library libffi. If you
would like to use the features that it enables, make sure that it is compiled
for the same architecture as your Haskell compiler (e.g. 64 bit libraries
for 64 bit ghc). By default, Idris builds without it. To build with it, pass
the flag -f FFI.

To build with libffi by default, create a custom.mk file and add the
following line to it:

CABALFLAGS += -f FFI

The file custom.mk-alldeps is a suitable example.

The continuous integration builds on travis-ci.org are built using the
ghc-flag -Werror. To enable this behaviour locally also, please compile
using make CI=true or adding the following line into custom.mk:

CI = true

If you are only compiling for installing the most current version, you can
omit the CI flag, but please make sure you use it if you want to contribute.

Code Generation

Idris has support for external code generators. Supplied with the distribution
is a C code generator to compile executables, and a JavaScript code generator
with support for node.js and browser JavaScript.

More Information

If you would like to find out more information, or ask questions, we
currently have a Wiki;
a mailing list,
and an IRC channel #idris on freenode. To join the IRC channel,
point your irc client to chat.freenode.net then /join #idris.

For those further interested in using Idris for projects, the
Idris Hackers GitHub organisation is
where some interesting projects are being hosted.

For those interested in contributing to Idris directly we kindly ask that
prospective developers please consult the Contributing Guide first.